This repository shows two patterns for server->browser async reporting of long-running task results using SignalR core. A running example can be found at: https://signalrprogress.azurewebsites.net/. The Home page is a simplified example using SignalR with an Ajax POST and the NoPost page shows a more worked-up example with multiple message types (and no POSTs :-)).
There is a walk-through of the Async POST pattern (simplified: best place to start) and a walk-through of the No POST pattern which is more complex/real.